[Cybersixgill] Add dashboard and update Icon

[P1llus]

What does this PR do?

Uses a better Icon for the package, adds dashboards and threat.feed.* fields

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.

[elasticmachine]

Pinging @elastic/security-external-integrations (Team:Security-External Integrations)

[elasticmachine]

💚 Build Succeeded

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Start Time: 2021-12-13T09:17:08.876+0000

• Duration: 14 min 16 sec

• Commit: 3859390

Test stats 🧪

Test	Results
Failed	0
Passed	9
Skipped	0
Total	9

🤖 GitHub comments

To re-run your PR in the CI, just comment with:

• /test : Re-trigger the build.